Pump



March 12,1968 P. HAMMELMANN PUMP 4 2 Sheets-Sheet 1 I Filed July 6. 1966 N mt Inventor 4AM i 10/61.

March 12, 1968 I p HAMMELMANN 3,372,648

United States Patent 3,372,648 PUMP Paul Hammelmann, 17 Zum Suudern, 474 Oelde, Westphalia, Germany Filed July 6, 1966, Ser. No. 563,253 Claims priority, application Germany, July 7, 1965, H 56,510 Claims. (Cl. 103--153) ABSTRACT OF THE DISCLOSURE A pump including a reciprocatable crosshead having a front portion in form of a cylinder, a stationary hollow piston extending into the cylinder of the c-rosshead coaxially arranged therewith, and a pair of valves respectively arranged in a pair of passage means communicating with the interior of said hollow piston and respectively opening and closing during movement of said crosshead along a suction stroke and a compression stroke.

The present invention relates to a pump and more specifically to a pump head for pressure pumps or the like.

Pump heads are known in which the piston of the pump is reciprocated, for instance by means of a crosshead, in a pump cylinder for producing an over-respectively underpressure in the latter.

In such an arrangement a perfect construction of the sealing means between the piston and the cylinder of the pump and an exact guiding of the piston is required, especially when the pump has to feed fluid under considerable pressure. When the sealing means becomes leaky, the fluid to be pumped will escape through the leaking sealing means with high speed in direction toward the drive means of the pump, so that the danger exists that the pumped medium mixes with the oil used for lubricating the drive mechanism of the pump.

It is one object of the present invention to provide for a pump head construction in which mixing of the pumped medium with the lubricating oil of the dg ive mechanism is positively avoided.

Another diihculty residing in pump constructions of the aforementioned type is that the proper guiding for the movable element of the pump head as well as a proper guiding of the crosshead connected to the movable element of the pump for reciprocating the latter has to be provided. In order to maintain optimum operating condiditions and resulting long usable life of the pump, it is desirable to properly align the piston and the cylinder of the pump as well as the crosshead along a common center line. It is further highly desirable in such pump constructions to arrange the various elements of the pump head in such a manner that they can be easily inspected and easily exchanged, when an exchange becomes necessary.

It is therefore a further object of the present invention to provide for a pumpheadconstruction in which proper alignment of the pump parts and the crosshead connected thereto is assured with an arrangement which is simple in construction and requires a minimum of material, and in which the pump head is constructed also in such a manner that the parts thereof may be easily inspected and replaced, when necessary.

It is a further object of the present invention to provide for a pump head in which the amount of fiuid pumped during each pumping cycle and the pressure of the pumped fluid may be easily changed.

With these and other objects in view, the pump according to the present invention mainly comprises support means and crosshead means guided in the support means for reciprocating movement. The crosshead means has a front portion in the form of a cylinder and this cylinder 3,372,648 Patented Mar. 12, 1968 has an end wall closing the cylinder at the end thereof joined to the remainder of the crosshead means. The pump comprises further a hollow piston means fixedly mounted on the support means and extending coaxially with the cylinder from the other end thereof into the latter. Moving means are also provided connected to the crosshead means for reciprocating the latter along a suction stroke and an opposite pressure stroke and the pump comprises further first passage means communicating with the interior of the hollow piston means for feeding fluid to be pumped .thereinto, suction valve means in the first passage means, second passage means communicating with the interior of the hollow piston means for discharging pressure fluid therefrom, and pressure valve means in the second passage means. The suction. valve means and the pressure valve means are arranged and constructed so that the suction valve means opens said first passage means during the suction stroke of the crosshead and the cylinder formed by the front portion thereof, while the pressure valve means is closed, and so that the pressure valve means is opened during the pressure stroke while the suction valve means is closed.

The support means are preferably in the form of a housing provided with a bore wherein the crosshead means is slidably guided and the hollow piston means are fixedly arranged in the bore coaxial with the cylinder portion of the crosshead means, whereas the first and second passage means are at least in part formed in the housing. The pressure and suction valve means are respectively arranged in the interior of the hollow stationary piston means and about one portion of the latter. I

The arrangement includes also annular sealing means between the stationary hollow piston means and the movable cylinder and the annular sealing means are either connected to the end of the hollow piston means facing the end wall of the cylinder or to the free end of the cylinder facing away from the end wall thereof. The bore through the housing is formed, intermediate the portion thereof in which a part of the hollow piston means is tightly fitted and another axially spaced portion in which the crosshead means is slidably guided, with an enlarged diameter portion forming a receiving chamber and passage means are provided leading from the side of the sealing means facing the other end of the cylinder to the receiving chamber so that fluid leading through the sealing means may pass into the receiving chamber. The latter is connected by a passage either to the atmosphere or to the suction space of the pump so that a mixing of the pumped medium with the lubricating oil. of the drive for the pump is positively avoided.

In order to change the amount of fluid pumped during each pumping cycle, an elongated member may be removably fixed at one end thereof to the end wall of the cylinder projecting therefrom into the hollow piston means. In this arrangement an annular sealing means may be provided between the elongated member and the hollow piston means, which sealing means is fixed to the other end of the elongated member.

The bore in the housing may be provided with means forming an annular shoulder between opposite ends of the bore and the hollow piston means is preferably formed intermediate its ends with a corresponding shoulder engaging said shoulder in the bore. This arrangement preferably includes a screw plug threadingly connected to one end of the bore for closing the latter and the end of the hollow piston means adjacent said one end of the bore and for pressing the shoulder of the piston means against the means forming the shoulder in the bore, so that the hollow piston means is removable from the bore upon unscrewing of the screw plug.

The novel features which are considered as characteristic for the invention are set forth in particular in the 3 appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings, in which:

FIG. 1 is a longitudinal cross section through the pump of the present invention; and

FIG. 2 is a partial cross sectional view of the pump head of the pump, drawn to an enlarged scale.

Referring now to the drawings, and more specifically to P16. 1, it will be seen that the pump according to the present invention includes a crank casing 1 in which a crank shaft 2 is mounted on bearings of known construction not illustrated in FIG. 1. The crankshaft 2 is driven by any conventional means not shown in the drawing and located outside of the casing 1. The crankshaft 2 is connected by means of a connecting rod 3 and a bolt 4 extending transversely through an end of the connecting rod distant from the crankshaft to a crosshead 5. The crosshead 5 has preferably a cylindrical outer surface and is formed at the front portion thereof facing away from the crankshaft 2 as a hollow cylinder 5a. The cylindrical crosshead 5 is guided for reciprocating movement imparted thereto by the rotating crankshaft 2 in a bore of a housing 8. The housing 8 is connected by screws, as shown in FIG. 1, to the crankshaft casing 1. Stationary hollow piston means are provided in a portion of the aforementioned bore axially spaced from the bore portion in which the crosshead 5 is guided and the hollow piston means are preferably formed from three parts 7, 11 and 12, as best shown in FIG. 2, which abut with end faces thereof against each other. The part 7 of the hollow piston means has a rear portion of the diameter substantially equal to the diameter of the bore so as to fit tightly therein, whereas the front portion of the part 7 has a reduced diameter portion which projects into the cylinder 5a formed on the crosshead 5. The bore portion in which the enlarged portion of the part 7 is arranged is formed with an annular groove in which a two-part ring is located projecting beyond the inner surface of this bore portion and forming a shoulder therein, and the large diameter portion of the part 7 is formed with a corresponding shoulder abutting against the shoulder formed by the two-part ring 15. A screw plug 7 is screwed in the end of the bore in the housing 8 and engages an end face of the part 12 so as to maintain the parts 12, 11 and 7 in abutting relationship and to press the shoulder on the part 7 against the shoulder formed by the two-part ring 15. This arrangement provides not only for a perfect alignment of the hollow piston means 7, 11 and 12 with the crosshead 5 and the cylinder 5a formed thereon, but this arrangement permits also for an easy assembly and disassembly of the hollow piston means with the other parts of the pump head.

The part 11 is formed at the inner surface thereof with a first valve seat with which the valve member 19 of a suction valve cooperates. The valve member 19 has a cylindrical portion projecting away from the valve seat which is guided for movement in axial direction in a corresponding cylindrical portion of a guide and support member 14 which has a plurality of arms clamped between correspondingly shaped ends of the parts 7 and 11. A compression coil spring 13 abutting against the valve member 19 and the guide and support member 14- is biased so as to tend to maintain the valve member 19 in engagement with its valve seat.

The part 11 has distant from the part 7 a reduced diameter portion so as to form a shoulder between this reduced diameter portion and the remainder of the part 11, and an annular valve seat is provided on this shoulder with which the annular valve member 9 of a pressure valve cooperates. The annular valve member 9 is pressed against its valve seat by a plurality of coil springs 10 partly housed in bores of the part .12 and engaging the annular member 9 so as to resiliently maintain the latter in abutment with its valve seat. Passage means 18 provide communication between a supply of fluid, not shown in the drawing, and the cylindrical space defined by the hollow members 12 and 11, upstream of the suction valve 19. Corresponding passage means lead from the space in the member 11 downstream of the suction valve 19 to the annular valve seat cooperating with the annular pressure valve member 9 and downstream of this pressure valve passage means lead to a reservoir or the like, not shown in the drawing, to which the fiuid pumped 'by the pump has to be supplied.

The pump arrangement of the present invention further includes annular sealing means between the cylinder 5a of the crosshead and the hollow piston means, respectively the part 7 thereof. The annular sealing means may include as best shown in FIG. 2, an annular sealing member 6 of resiliently compressible material, which may have a cross section as shown in FIG. 2, and a threaded ring or bushing 25 threadingly connected to the part 7 in the region of the free end of the latter so that by adjusting the threaded bushing 25 in axial direction of the part 7 the compressible sealing member 6 may be compressed between the bushing 25 and a ring 25a held by a snap ring or the like in fixed position at the free end of the piston part 7. The aforementioned parts 6, 25 and 25a forming the annular sealing means may directly engage the inner surface of the cylinder 5a, but preferably, as shown in the drawing, an elongated bushing 23 is provided threadingly connected to a correspondingly threaded end of the cylinder 5a and snugly fitting into the latter so that the compressed resilient annular sealing member 6 is in sealing engagement with the outer surface of the part 7 and the inner surface of the bushing 23. The inner surface of the bushing 23 has preferably a diameter slight ly larger than the outer surface of the part 7 extending thereinto so as to form a passage leading from the face of the threaded ring 25 which is opposite the face thereof engaging the annular sealing member 6 into portion of the bore in the housing 8 adjacent a portion of this bore of enlarged diameter forming a receiving chamber 7a. The receiving chamber 7a communicates either by a passage, not shown in the drawing, with the outer atmosphere or through another passage 6a, with the interior of the part 11 upstream of the suction valve 19. In this arrangement, if the annular sealing means 6, 25 and 25a become leaky, passage of fluid leaking through the sealing means into the crank casing 1 which is partly filled with lubricating oil is positively avoided, since the leaking fluid will pass through the passage 6b into the receiving chamber 7a and from there either to the outside of the housing 8 or into the suction space of the pump.

The above-described arrangement not only provides for a proper axial alignment of the crosshead 5 and the cylinder 5a formed thereon with the hollow piston means 7, 11 and 12 and the annular sealing means 6, 25, 25a on the part 7 of the hollow piston means, but the aforementioned described arrangement also permits easy assembly and disassembly of the various parts forming the pump head and inspection of the parts, respectively replacement thereof, if such replacement should become necessary.

The pump construction according to the present invention permits also to change the amount of fluid pumped during each pumping cycle in an extremely simple manner. This can, for instance, be accomplished by exchanging the part 7 of the hollow piston means and the annular sealing means thereon against corresponding parts of different diameter.

However, it is also possible to change the amount of fluid pumped during each pumping cycle, while maintaining the part 7 of the hollow piston means, by providing an elongated member 20 fixed to the cylinder 5a and projecting into the bore of the stationary part 7 of the hollow piston means. The elongated member 20 is preferably of cylindrical form having a diameter smaller than the inner diameter of the part 7. The right end 20a, as viewed in FIG. 2, of the elongated member 20 preferably abuts against the end wall of the cylinder a and has a diameter substantially equal to the inner diameter of the cylinder so as to fit tightly therein. The bushing 23 abuts with its right end, as viewed in FIG. 2, against the end portion Zila of the elongated member to hold the end portion against the bottom wall of the cylinder 5a. The left end, as viewed in FIG. 2, of the elongated member 20 has preferably a reduced diameter portion and annular sealing means comprising a bushing 22, at least one, or preferably two annular sealing members 21 of elastically compressible material and preferably of a cross section as indicated in FIG. 2, and a snap ring 24 holding the sealing members 21 and the bushing 22 against a shoulder of the elongated member 2%. The annular sealing means 16, 21 and 22 provide a fluid-tight seal between the stationary part '7 of the hollow piston means and the member 20 which reciprocates with the crosshead means 5 and the cylinder 5a thereon. When the annular sealing means 21, 22 and 24 are used, the annular sealing means 6, 25 and 25a at the end of the part 7 of the hollow piston means may be omitted. By using the elongated member 20 the delivery of the pump is reduced, while the pressure of the pumped fluid is increased. For instance, in an actually built embodiment, the delivery of the pump without the elongated member 20 was 80 liters per minute at a pressure of 100 atmospheres, whereas during use of an appropriate elongated member 20 with the sealing means thereon the delivery of the pump was reduced to 40 liters per minute, whereas the pressure of the pumped fluid was increased to 200 atmospheres.

When the elongated member 20 is used without the annular sealing means thereon, the dead space of the pump is reduced.

The operation of the pump will be obvious from the above description. When the crosshead means 5 are moved by the crankshaft 2 toward the right,as viewed in FIG. 2, an underpressure will be created in the interior of the part 7 so that the suction valve 19 will open against the pressure of the spring 13 and fluid will be sucked through the passage 18 into the interior of the part 7. During the reverse pressure stroke of the crosshead means 5 and the cylinder 5a thereon, the suction valve will close whereas the pressure valve 9 will open so that fluid under pressure will be delivered through the passages which lead to and from the pressure valve to the point of use.

It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of pump differing from the types described above.

While the invention has been illustrated and described as embodied in a pump having stationary hollow piston means and a movable cylinder, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can by applying current knowledge readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims.

What is claimed as new and desired to be secured by Letters Patent is:

1. In a pump, in combination, support means; crosshead means guided in said support means for reciprocating movement, said crosshead means having a front portion in form of a cylinder, said cylinder having an end wall closing said cylinder at the end thereof joined to the remainder of said crosshead means, hollow piston means h fixedly mounted on said support means and extending from the other end of said cylinder into the latter coaxially arranged therewith; an elongated member having an end portion of larger diameter than the remainder thereof abutting against said end wall and projecting therefrom into said hollow piston means; a bushing threadingly connected at one end thereof to said other end of said cylinder and projecting from said connected end into said cylinder to engage with the other end thereof a face of said end portion facing away from said end wall for maintaining said end portion of said elongated member in abutment with said end wall; moving means connected to said crosshead means for reciprocating the same along a suction stroke and an opposite pressure stroke; first pasage means communicatin with the interior of said hollow piston for passage of fluid to be pumped thereinto; suction valve means in said first passage means; second passage mean communicating with the interior of said hollow piston means for discharging fluid under pressure therefrom; and pressure valve means in said second passage means, said suction valve means and said pressure valve means being arranged and constructed so that said suction valve means opens said first passage means during the suction stroke of said crosshead means while said pressure valve means is closed and so that said pressure valve means is opened during the pressure stroke of said crosshead means while said suction valve means is closed.

2. In a pump as set forth in claim 1, wherein said support means are in the form of a housing and provided with a bore, said crosshead means being slidably guided in said bore, said hollow piston means being fixedly arranged in said bore coaxially with the cylinder portion of said crosshead means, and said first and second passage means being in part formed in said housing.

3. In a pump as set forth in claim 2, wherein said suction valve means and said pressure valve means are provided in said piston means and including annular sealing means between said cylinder of said crosshead means and said piston means.

4. In a pump as set forth in claim 3, wherein said annular sealing means is provided on the end of said piston means facing said end wall of said cylinder.

5. In a pump as set forth in claim 4, wherein said crosshead means is slidably guided in a first portion of said bore of said housing and said piston means is fixed in and tightly engaging a second bore portion axially spaced from the first bore portion, and wherein said bore has a third bore portion located between and having a diameter greater than that of said first and said second bore portions and forming a receiving chamber, and including passage means leading from the side of said sealing means facing said other end of said cylinder to said receiving chamber so that fluid leaking through said sealing means may pass into said sealing chamber.

6. In a pump as set forth in claim 5, and including additional passage means providing communication between said receiving chamber and the interior of said hollow piston means upstream of said suction valve means.

7. In a pump as set forth in claim 3, wherein said annular sealing means is arranged on said other end of said cylinder.

8. In a pump as set forth in claim 1, and including annular sealing means between said elongated member and said hollow piston means, said sealing means being fixed to the other end of said elongated member.

9. In a pump as set forth in claim 1, and including annular sealing means fixed to the end of said hollow piston means facing said end wall of said cylinder and sealingly engaging with the outer surface thereof the inner surface of said bushing.

10. In a pump as set forth in annular sealing means fixed to the other end of said elongated member and engaging with the outer surface thereof the inner surface of said hollow piston means.

claim ll, and including 11. In a pump, in combination, support means in form of a housing provided with a bore; crosshead means slidably guided in said bore for reciprocating movement, said crosshead means having a front portion in form of a cylinder, said cylinder having an end Wall closing said cylinder at the end thereof joined to the remainder of said crosshead means; means in said bore of said housing forming an annular shoulder between opposite ends of said bore; hollow piston means extending from the other end of said cylinder into the latter coaxially arranged therewith and having intermediate its ends a shoulder engaging said annular shoulder in said bore; a screw plug threadingly connected to one end of said bore and closing the latter and the end of said hollow piston means adjacent said one end of said bore and pressing said shoulder of said piston means against said means forming said shoulder in said bore, said hollow piston means being removable from said bore upon unscrewing of said screw plug; moving means connected to said crosshead means for reciprocating the same along a suction stroke and an opposite pressure stroke; first passage means communicating with the interior of said hollow piston for passage of fluid to be pumped thereinto; suction valve means in said first passage means; second passage means communicating with the interior of said 'hollow piston means for discharging fluid under pressure therefrom; and pressure valve means in said second passage means, said suction valve means and said pressure valve means being arranged and constructed so that said suction valve means opens said first passage means during the suction stroke of said crosshead means while said pressure valve means is closed and so that said pressure valve means is opened during the pressure stroke of said crosshead means while said suction valve means is closed.

12. In a pump as set forth in claim 11, wherein said hollow piston means is formed from three hollow cylindrical parts arranged coaxial with and abutting against each other in said bore, one of said three parts abutting against said means forming said shoulder in said bore, a second part abutting against said screw plug, and a third part being located between said first and said second part and being formed in the interior thereof with a first valve 8 seat and at the exterior thereof with a second annular valve seat, said suction valve means having a valve member cooperating with the first valve seat, and the pressure valve means having an annular valve member cooperating with said second annular valve seat.

13. In a pump as set forth in claim 12, wherein said suction valve means includes further a guide member held between abutting ends of said first and third part of said piston means for guiding said valve member in axial direction, and spring means between said valve member and said guide member and biassed so as to press said valve member against said first valve seat.

14. In a pump as set forth in claim 12, wherein said third part of said piston means has a portion of reduced diameter abutting against said second part, said annular valve member of said pressure valve means being guided on said portion of reduced diameter, and said pressure valve means including spring means engaging at opposite ends thereof said annular valve member and said second part of said hollow piston means and being biassed so as to press said annular valve member against said second annular valve seat.

15. In a pump as set forth in claim 14, wherein said three parts of said hollow piston and said annular valve member have maximum outer diameters substantially equal to the inner diameter of said bore in said housing.

References Cited UNITED STATES PATENTS 1,603,675 10/1926 Folsom et al 103-158 1,857,026 5/1932 Ligon 103l58 2,048,098 7/1936 Bohnenblust 103-153 2,274,241 2/1942 Lemanski 103-163 2,732,809 1/1956 Mattingly et al 103--153 2,981,198 4/1961 Nettel l03-178 3,263,622 8/1966 Tyree l03163 FOREIGN PATENTS 915,526 7/ 1954 Germany.

HENRY F. 'RADUAZO, Primary Examiner. 

